Queensland state Premier Anna Bligh said the ship's operators would be liable for the costs.
"We are investigating the entire incident and if there is any basis for a prosecution, we will not hesitate to take that action - the total cost of the clean-up will rest with this company."
The ship's owner, Swire Shipping, may face fines of up to A$1.5m ($977,000; £703,000) if found guilty of environmental breaches, as well as clean-up costs of A$100,000 a day.
Experts fear the toxic chemicals will suffocate fish and kill natural habitats
Maritime officials said 31 containers of ammonium nitrate fertiliser fell from the deck in huge swells, puncturing the Pacific Adventurer's hull and releasing the oil.
The ship was en route from a port south of Queensland's state capital, Brisbane, to Indonesia.
Environmental experts fear the nutrient-rich fertiliser could cause damaging algal blooms, suffocate fish and kill natural habitats.
Moreton and Bribie Islands are national parks - home to a range of sea birds and creatures, including turtles, dolphins and pelicans.
The Environmental Protection Authority (EPA) said it had begun removing the oil from the beaches and was treating oil-affected wildlife.
Radar-equipped aircraft are searching for the missing containers of fertiliser - which can be used to make explosives.
Bookmark with:
What are these?